Congratulations on finding your way to WikiTree! The page Ros referred you to should be very helpful with getting your GEDCOM uploaded. There are some things you may want to know which are not on that page, and which those of us who have been here for awhile have learned.
1-Because WikiTree is one family tree that we all share, the best way to handle your GEDCOM upload is to simply link your family members who are not on the tree to those who already are, so that you don't create needless duplicates.
2- If you have further information on some of your family members, particularly conflicting information, make sure that each point is researched well and documented with good sources. You are aware that sourcing facts is a part of WikiTree's Honor Code. A difference between WikiTree and other sites is that genealogists who have been using Ancestry.com or MyHeritage, etc., have had sources somewhat spoon-fed them through hints. (I have been a member of both of those sites.) At WikiTree, it is important to double-check the sources you have from those sites to make sure they actually apply to the profile you are working on. Reading through the Help:Sources page at https://www.wikitree.com/wiki/Help:Sources,
and then following some of the links on that page, is very helpful for this part of building profiles.
3-The other really important thing to remember about WikiTree is that collaboration is an important part of WikiTree. One way that that comes into play is when you want to add information that you have on a person to their profile which someone else manages. If the profile manager is active on that profile, it is important to message them about any significant changes you want to make BEFORE you make the changes. This is showing WikiTree love. Also, it is very important that you add information only after you make sure that it is sourced. Because ancestry.com is behind a paywall, sources from familysearch.org (which is a free site) are preferred. A lot of the information available on ancestry.com is also available on familysearch.org and it is worth it to go there to find sources that everyone can access.
4- Research hint: On each profile, you will find a Research link on the bottom right-hand side. Once you follow the link and fill the info in the form, you can click on Family Search and it should automatically populate the research form. (Sometimes I have to click twice to get the page to populate properly.) It is very easy then to research the person. You do have to create an account now to use familysearch.org, but it is definitely worth it. Using sources that are available to everyone helps your profiles.
If you follow these tips, you will be showing everyone your WikiTree love! Again, welcome to WikiTree and good searching! G2G is the place to go for your questions!